EFFECTS OF DIFFERENT PHOSPHORUS IMMOBILIZATION WAYS ON|PHOSPHORUS SORPTION BEHAVIORS IN SEDIMENT OF LAKE CHAOHU

Internal phosphorus loading in sediment will exert negative effects on restoration of eutrophic lakes, whosecontrol is dependent on the effective enhancement of phosphorus sorption on sediments, but relevant works are scare. Inthis study, the sediments from the seriously polluted areas in a Chinese eutrophic lake (Lake Chaohu) were obtained, andthe effects of the routine technologies such as dosing salts of calcium, iron, aluminium and aeration, on sedimentsphosphorus sorption behavior and interstitial water soluble reactive phosphorus (SRP) concentration were comparedwith the application of calcium salt, no significant changes in phosphorus sorption maximum and the bonding energywere observed, together with the slight decrease in SRP concentration in interstitial water and zero equilibrium phosphorusconcentration (EPC0) in sediment; furthermore, the application of salts of iron and aluminium not only significantenhanced phosphorus sorption maximum and the bonding energy, but also decreased SRP concentration in interstitialwater and EPC0 in sediments, leading to a stronger ability to adsorb phosphate from aqueous phase into sediment.With the lowest dosage, iron salt could reduce sediment EPC0 more effective relative to aluminium salt; on the otherhand, aeration had no significant effects on phosphorus sorption maximum and the bonding energy, and what is worse, itsubstantially gave rise to SRP concentration in interstitial water and sediment EPC0 value, thereby increasing risk ofphosphorus release. Overall, iron salt application with optimal dosage can be taken as a suitable technology for sedimentremediation of eutrophic lakes, while the benthic aeration must be cautiously used.